Yarn treatment



- No Drawing.

Patented a1, 19, 1932 UNITED STATES PATENT OFFICE JACK L. BITTER ANDRICHARD ELSSNER, OI JOHNSON CITY, TETINESSEE, ASSIGNORS TO AMERICANGLAN'ZSTOFF CORPORATION, OI. NEW YORK, .N'. Y.,-A CORPORATION OFDELAWARE after passing through the coagulating medi um, is wound in thewet form upon a spool which might be any of the well known forms,

such as perforated, laminated, or corrugated. The threads of this yarnare then washed, and, for example in the viscose process, desulphurized,as well as bleached, etc. After the wet treatment, the yarn is usuallydried by a drier or a drying process which circulates hot air throughand over the surfaces of the same while it is still on the spools. Byfollowing the usual processes the yarn is ordinarily allowed to dry bothfrom the outer and inner surface towards the middle thereof. By thisprocess the outer and inner portlon of the thread body are first driedand have a tendency to shrink and then the center portion is dried.Inasmuch as the innermost layers rest upon a solid bobbin or spool, andthe outermost layers .are resting upon the middle layers, which aredrying last, the outer and inner portions do not have sufficient chanceto shrink in the same way the middle layer does. This causes an unevenshrinkage, or contraction of the filaments comprising the yarn body andis very undesirable.

Our present invention has to do with a new method of drying and treatingthe filaments so that a high and uneven shrinkage or contraction istotally eliminated.

One method whereby our new process may be accomplished follows:

The yarn is extruded as usual and wound upon any ordinary type of bobbinor spool. Then a cloth or other suitable air and liquid tight coveringof suflicient thickness is wrapped about the spool so that all themoisture contained in the yarn must be dried out from the inside. Thespool is then placed in Application filed Jul 2,1931. Serial in.548,474.

for the inner filaments, are indicated.

the drier and allowed to dry as usual. wrapping causes the inner andmiddle layers of the yarn .to become dried first thereby giving theouter layers room within which to shrink. After thus drying the yarnbody upon the spool, the spool or bobbin is then placed upon a rewindingmachine, as, for example, a twisting machine, a winding machine, etc'.,and the yarn wound upon another bobbin or spool, so that the resultingyarn body is loose and room is allowed for shrinking. By this rewindingthe position of the yarn body is changed about and the layers which wereon the outside before are now upon the inner side. The spool is thenrewet,

wrapped again'witha sufficient amount of cloth or a water and air tightcovering of siutable material so that moisture can only This be takenout from the inside and again placed in the dryer. This drying allowsthe inner layers or the middle layers to dry first, as in the first casethereby giving theouter layer,

which was before the inner layer, suflicient room within whichto shrinkto the same degree that was obtained in the other two layers. Theperformance of the second drying gives a yarn body the parts of whichare all evenly dried and therefore evenly shrunk.

Graphs have been made, depicting the evenness (or unevenness) of dryingof artificial filaments when different processes are used. Results showthat in the old direct spool process, described in paragraph four of thepresent specification, the drying produces a very uneven shrinkage ofthe yarn or filaments being treated. A shrinking of approximately 3.4%on the inside of the spool, of approximately 2.5% on the outside, andvarying percentages of shrinking, varying irregularly,

owever, when the outer surfaces of the spooled filaments are covered,usually with a flexible, water-tight covering, as indicated above, amore even shrinkage curve results. The shrinkage when the applicantspresent process is used more nearly approaches that of skein drying.Because drying the filaments in skein form involves many extra steps andis comparativelyexpensive, it may be easily seen that the presentprocess covers a great step forward in the art. I 4

Although we have hereinbefore described specifically one method wherebythe yarn- 5 might be driedin one direction only, rewet,

.drying' the same rewound, and dried in the other direction-because ofthe changed space of the yarn, it must be understood that we do notdesire to limit ourselves to this specific modification but theinvention includes within its purview whatever changes that come withinthe terms or 1spirit of the appended claims.

I aving now fully set forth our invention as required by the patentstatutes, what we desire to claim is:

1. In a method for drying artificial filaments wound upon a perforatedbobbin, the step of removing the moisture from the yarn body in onedirection only the outer surface of the filaments with an impermeablecovering, and then applying a dry- 111% medium to the inner side only ofthe b0 bin so that the yarn body dries from the inner side only.

2. In a process for drying artificial yarn which has been collected on aforaminous holder, the step of covering the outer surface of the yarnbod with an impermeable covering, and applylng the drying medium to theinner side of the holder so that the yarn body dries only from the innerside.

3. A. process as set forth in claim 1, wherein the yarn is rewound ontoanother bobbin, rewet, and then redried from the inside only.

4. The process as set forth in claim 2,

wherein the yarn is then rewound upon another similar holder, so that aloose w1nding.

results and the filaments are then rewet and redrie 5. In a process ofthe class described, the steps of wrapping wet artificial yarn woundupon a perforated spool with an impermeable covering, and then applyinga drying" medium to the inner surface of the spool, thus drying theyarn'from the inner side of the spool only.

6. In a process for drying artificial yarn, filaments, etc., upon aforammated spool, the steps ofcoverin the outer surface of the filamentsetc., wit an impermeable covering,

from the inside only by introducing a drying medium to the inner side ofthe spool, rewinding onto another spool or bobbin, rewetting thefilaments, and then redrying, with the use of an impermeable cover, fromthe inside of the spool onl In testimony whereof we :xour signatures.

DR. JACK L. BITTER. DR. RICHARD ELSSNER.

by first covering,

